Cat and Alex are excited to be at the world's most popular comics convention--and they're even more excited to compete in the Quest, a huge scavenger hunt run by their favorite nerdy celebrity. The big prize: a chance to meet him! The twins ditch their older sister Fi and set off to find geeky clues, tackle nerdy challenges, and cross as many items as possible off their Quest list, which includes volunteering at an Artist Alley booth, gathering cosplayers in enough colors to make a double rainbow, and actually finding something healthy to eat in the convention center! Can the twins work together even when they disagree on how to compete? Will Fi find Cat and Alex before their parents realize they're missing? Most importantly, can these ultimate fans complete the ultimate Quest?